Small bowel biopsy is a diagnostic procedure in which a portion of the lining of the small intestine is removed for examination.

Small bowel biopsy samples are usually obtained by EGD or colonoscopy. During an EGD, a flexible tube (endoscope) is inserted through the mouth or nose and into the upper gastrointestinal tract. During a colonoscopy, a flexible tube is inserted through your rectum, through the colon, and into the end part of the small intestine. Tissue samples removed during endoscopy are sent to the laboratory for examination.

Preparation for this test is similar to that for an EGD. Fasting for at least 4 hours is recommended. You must sign a consent form.

Infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

The passage of the tube and capsule often makes a person feel like gagging (topical anesthetic is used to minimize this sensation).

A mild sedative can be given, but only in small doses because the person must remain alert enough to assist with the procedure (by doing such things as swallowing and turning). The biopsy sampling causes little or no pain, although it may cause some mild cramping.

This test is most often performed to help diagnose diseases of the small intestines.

Normal small bowel tissue includes finger-like projections (villi), crypts, columnar epithelial cells, and round cells.

Abnormal findings may include:

• Ulcers
• Polyps
• Abnormalities of the mucosa or villi (for example, flattening)
• Radiation enteritis
• PAS positive macrophages (specific type of immune cells)
• Swollen or enlarged intestinal lymph nodes or lymphatic vessels

Disorders and conditions that may be indicated by changes found on small bowel biopsy include:

• Celiac sprue
• Coccidiosis
• Folate or Vitamin B12 deficiency
• Giardiasis
• Infectious gastroenteritis
• Crohn's disease  
• Amyloidosis
• Lymphangiectasia
• Lymphoma
• Malnutrition
• Tropical sprue
• Whipple's disease

Additional conditions under which the test may be performed include lactose intolerance.

Complications are rare but may include:

• Bowel perforation (hole in the bowel)
• Excessive bleeding from the biopsy site
• Infection of the biopsy site leading to bacteremia 
• Vomiting and subsequent aspiration into the lungs

Contraindications (factors that prohibit use of this test) may include uncooperative or confused patients, people taking aspirin or anticoagulants (greatly increases risk of bleeding), and people with untreated coagulation (blood clotting) disorders.

The greatest risk is bleeding. Signs include abdominal pain, blood in the stools, or vomiting blood.